Wireless communication networks are widely deployed to provide various communication services such as voice, packet data, multi-media broadcast, and text messaging. These wireless communication networks may be multiple-access systems capable of supporting communication for multiple users by sharing the available network resources. Examples of such multiple-access systems include Code Division Multiple Access (CDMA) systems, Time Division Multiple Access (TDMA) systems, Frequency Division Multiple Access (FDMA) systems, and Orthogonal Frequency Division Multiple Access (OFDMA) systems. A CDMA system may implement Wideband CDMA (W-CDMA), and cdma2000. W-CDMA is described in documents from 3rd Generation Partnership Project (3GPP). CDMA2000 is described in documents from 3rd Generation Partnership Project 2 (3GPP2). 3GPP and 3GPP2 documents are publicly available. WiMAX (Worldwide Interoperability for Microwave Access)-based systems are being designed and developed for operation in licensed bands, such as 2.3 GHz, 2.5 GHz, 3.3 GHz, 3.5 GHz etc.
Existing Time Division Duplex (TDD) wireless communication networks typically specify an interval between an end of a downlink frame and a beginning of a subsequent uplink frame to allow the remote devices to decode the downlink frame and prepare for the uplink frame. However, the duration of the time interval imposes a limitation on the maximum distance between a downlink frame transmitter and a remote device that transmits the uplink frame in response to the downlink frame. As the remote device becomes more distant from a network node, the round trip delay between transmission of the downlink frame and reception of the uplink frame increases and therefore more bandwidth is consumed. The delay in the reception of the UL frame also increases interference. For the network node, it may be challenging to allocate system resources for such transmissions in an efficient manner.
Accordingly, there is a need for an improved and more efficient method and apparatus for optimizing downlink transmission in a wireless communication network.
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The apparatus and method components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.